The pathophysiology of nasal polyp disease is complex and the etiology is elusive. Nasal polyps often coexist with asthma, allergic rhinitis and aspirin intolerance. An inflammatory infiltrate primarily composed of eosinophils is characteristic of the majority of nasal polyps regardless of the cause. Standard treatment with topical nasal steroids, systemic corticosteroids and surgical removal ofter fails. Zileuton has been shown to be a potent and selective inhibitor of 5-lipoxygenase activity. Improvement in nasal symptoms and polyp size in patients treated with zileuton has been anectdotally observed. The purpose of this study is to compare the efficacy of zileuton and placebo in nasal polyp disease.